The present invention relates to a cooling/heating apparatus for a semiconductor processing liquid applied to a cooling/heating unit of a thermoregulator used to control temperature of semiconductor processing corrosive chemicals.
In a cooling/heating apparatus for a semiconductor processing liquid having heat exchanging substrates to cool or heat a corrosive semiconductor processing liquid so as to keep the liquid at a designated temperature, most of the heat exchanging substrates used are generally configured such that a sheet of fluorine-contained resin (for which the trade name is TEFLON) etched with plasma or sodium is joined by the medium of an adhesive layer of epoxy resin or other adhesives to a processing liquid contact surface side of a stainless steel plate or a graphite substrate. In the case of these conventional heat exchanging substrates, however, when highly corrosive chemicals are cooled or heated, the chemicals, even though slightly, infiltrate through the fluorine-contained resin sheet, which may cause the adhesive to be dissolved out of the adhesive layer between the stainless steel plate or the graphite substrate and the sheet. Particularly, when using a stainless steel plate, the stainless steel is attacked by the chemicals as the adhesive is dissolved out and a metallic ion may subsequently be dissolved in the chemicals as an impurity. Also, in either case, there is a problem pointed out that chemicals applicable can be limited depending on thermal resistance of adhesives.
It is therefore an object of the present invention to provide a cooling/heating apparatus for a semiconductor processing liquid having heat exchanging substrates which is highly resistant to corrosive chemicals and is free from elution of harmful impurities such as a heavy metal ion.
To achieve the above object, according to a first embodiment of the present invention, there is provided a cooling/heating apparatus for a semiconductor processing liquid to cool or heat by allowing heat exchanging substrates to contact the semiconductor processing liquid, wherein the heat exchanging substrates are formed by heat-depositing a fluorine-contained resin sheet to a processing liquid contact surface of a graphite substrate.
Also, according to a second embodiment of the present invention, there is provided a cooling/heating apparatus for a semiconductor processing liquid, wherein heat exchanging substrates are formed by providing an amorphous carbon layer over a processing liquid contact surface of a graphite substrate and heat-depositing a fluorine-contained resin sheet to the amorphous carbon layer.
Furthermore, according to a third embodiment of the present invention, there is provided a cooling/heating apparatus for a semiconductor processing liquid, wherein heat exchanging substrates are formed by heat-depositing a fluorine-contained resin sheet to a processing liquid contact surface of a vitrified carbon substrate.
According to a fourth embodiment of the present invention, there is provided a cooling/heating apparatus for a semiconductor processing liquid, wherein the heat exchanging substrates are formed by heat-depositing a fluorine-contained resin sheet to a processing liquid contact surface of a silicon carbide substrate.
According to a fifth embodiment of the present invention, there is provided a cooling/heating apparatus for a semiconductor processing liquid, wherein the heat exchanging substrates are formed by providing a silicon carbide layer over a processing liquid contact surface of a graphite substrate and heat-depositing a fluorine-contained resin sheet to the silicon carbide layer.
In the cooling/heating apparatus for a semiconductor processing liquid of the present invention having the above construction, heat exchanging substrates are formed either by directly heat-depositing a fluorine-contained resin sheet to a processing liquid contact surface of a graphite substrate which is highly resistant to corrosive chemicals, a vitrified carbon substrate or a silicon carbide substrate, or by providing an amorphous carbon layer over a processing liquid contact surface of a graphite substrate or a silicon carbide substrate and directly heat-depositing a fluorine-contained resin sheet to the amorphous carbon layer so that the apparatus is free from elution of harmful impurities caused by the attachment of the chemicals to the adhesive layer, and moreover, elution of harmful impurities such as a heavy-metal ion caused by corrosion of the substrate itself is prevented as well.